The U.S. Air Force will this weekend deploy a small number of F-35A fighter jets to Europe for several weeks of training with other U.S. and NATO military aircraft, the Pentagon said Friday.

In a statement, the Pentagon said that the deployment would allow the U.S. Air Force to "further demonstrate the operational capabilities" of the stealth jet. It did not say where the aircraft would be sent.

The F-35, which is the Pentagon's costliest arms program, has been dogged by problems. The Pentagon's chief arms buyer once described as "acquisition malpractice" the decision to produce jets before completing development.

During last year's presidential election campaign, Donald Trump criticized Lockheed Martin Corp. for the F-35's cost overruns. Days after taking office in January, Trump announced his administration had been able to cut $600 million from the latest U.S. deal to buy about 90 F-35 Joint Strike Fighters.

The United States is expected to spend $391 billion over 15 years to buy about 2,443 of the F-35 aircraft.

F-35s are in use by the U.S. Air Force, Marine Corps and Navy, and by Australia, Britain, Norway, Italy, the Netherlands and Israel. Japan took delivery of its first jet in December.